Speed-indicator



(No Model.) 2 Sheets-Sheet 1.

R. J PRATT.

SPEED INDICATOR.

Patented June 3,1884.

no Model.) 2 SheetsSheet 2..

R.J.PRATT. SPEED INDICATOR.

No. 299,677; Patented June 3, 1884.

m. Ilia:

mum-um lllllllllll UNITED STATES 5 FATENT @Fiuo".

ROBERT JAMESPRATT, OF GREENBUSH HEIGHTS, NEW YORK.

SPEED-INDICATOR.

SPECIFICATION forming part of Letters Patent No. 299,677, dated June 3,1884.

Application filed January 2, 1884. (No model.)

To aZZ whom it may concern:

Be it known that .1, ROBERT J. PRATT, of Greenbush Heights, in thecounty of Rensselacr and State of New York, have invented certain newand useful Improvements in Speed -Indicators; and I do hereby declarethat the following is a full, clear, and exact description of theinvention, which will enable others skilled in the art to which itappertains to make and use the same, reference being had totheaccompanying drawings, and to the letters of reference markedthereon, which form part of this specification.

My invention relates to that class of devices for measuring andrecording the number of revolutions made by the armatureshaft of adynamo-machine, in which the motion of the shaft is transmitted by meansof a wormspindle to a toothed recording-dial intermeshing with thelatter.

Previous to my invention, hereinafter described, speed indicatorsembodying these generic features were, by reason of defects in theirspecific construction and the means adapted for clutching them upon theshaft, incapable of performing their function with the accuracy requiredin delicate calculations. It is the object of my improvement to ob viatethese difficulties; and for that purpose it consists in providing thedial with means for engaging it at will with the spindle, andautomatically throwing it out of gear with the latter when the recordingoperation is finished.

It further consists in providing the indicator with means for preventingabrasion of the dialteeth, and also in certain details of construction,as hereinafter described, and more particularly pointed out in theclaims.

In the drawings forming part of this application and hereunto annexed,Figure 1, Sheet 1, represents in plan my improved indicator. Fig. 2,Sheet 1, represents in cross-section upon the line y y, Fig. 1, therecording-dial. Fig. 3, Sheet 1, is a similar view upon the line 2 2,Fig. 1. Figs. 4 and 5, Sheet 1, represent, upon a smaller scale, sideand end elevations, respectively, of one of the means I employ forclamping the socket-clutch upon the armature-shaft. Figs. 6, 7,8, and 9,Sheet 2, are like views of modifications thereof.

In the several figures like letters indicate like parts.

The indicator proper consists of a framepiece, L, provided with theopposite bearings U and V, in which plays the worm-spindle R. Thespindle is provided with a fixed shoulder, T, and terminates in a squareor polygonal extension, S. At the point M is pivoted the arm W, slottedfor the reception of the graduated toothed dial 1?, and carrying on eachside an indicating-finger, o. The arm is provided with a detachabledial-guard, N, and extending through aslot in an offset, V, of thebearing V, terminates in a handle, W. In the slot is located a coiledspring, X, bearing against the frame and the arm, a set-screw, Y,regulating its tension. A second set-screw, Y, is inserted opposite ahigher offset on the bearing V, and limits the inward movement of thearm and dial. The dial is graduated on both sides from 1 to 100, thenumbers on the reverse side to that shown in the drawings running in anopposite direction thereto. If, therefore, the armature of the dynamorevolves in such a manner that the wheel WV is made to turn in adirection opposite to that indicated by the arrow in Fig. 1, itis merelynecessary to insert the indicator with the reverse side uppermost andread from the second dial-face. One hundred revolutions of the shaft andspindle effect a single revolution of the dial-wheel.

All the parts of the indicator are preferably of brass, exeeptthespindle and screws, which should be made of cast-steel.

In Figs. 4 to 9, inclusive, I have illustrated various means forsecuring and maintaining a firm connection between the indicatorspindleand the armature-shaft, which I find to be useful in connection with myinvention. The construction of these devices may be briefly summarizedas follows: In Figs 4 and 5 jawpieces B, hollowed out, as shown, andbearing the adjustable socket-bar D, may be clamped upon and releasedfrom the dynamo-shaft A by means of the screw-threaded rod 0, attachedto one of the jaw-pieces, and the butterfly-nut f, bearing against theother. In Figs. 6 and 7 the jaw-pieces are operated by right and lefthand screws G, and, converging upwardly, form supports for thecorrespondingly-hollowed under surfaces of the socket-bar carryingpieces II. In Figs. 8 and 9 is shown an annular socketed cap or shell,0, provided with bindingscrews It, and preferably with an internal splitcollar, 0, which may be varied in size to correspond to slightvariations between the shell and shaft.

The operation of my invention is as follows: Upon the end of the shaftis affixed one of the several modifications of clamping devices shown.In the socket-clutch of such clamp is inserted the extension S of theworm-spindle XV. The shaft is then set in motion and carries with it theclamp and spindle, the latter turning loosely in its bearings U and V.hen the shaft has attained the speed which it is desired to record, theoperator is enabled, by means of the handle of the pivoted arm, toinstantl y gear the indicating-dial with the wormshaft at the verybeginning of the period of time for which the velocity is to becalculated. At the end of such period the dial is as quickly disengaged,the recoil of the spring, when the handle is released, forcing thepivoted arm at once from the spindle. The presence of the set-screw Y,whose distance from its bearing on the offset It is so graduated thatthe arm shall approach during the recording operation only withsufficient nearness to fairly engage the worm with the dial-teeth,prevents the latter from being forced or crowded in upon the spindlewith so much frietionas to abrade or wear off their faces.

In applying my invention to dynamo-machines when a number of experimentshave to be made in succession, I have found it useful to secure theworm-spindle firmly to the clamping device and allow it to turn with thearmature during the running of the dynamo then, whenever a measurementis desired, the frame is slipped over the spindle, whence it may beremoved when the recording operation is completed, and until anothermeasurement is to be taken.

It is evident that my invention can be used in connection with othermachines where sin1i- 'lar calculations are required.

Having thus described my invention, what 1.

claim and desire to secure by Letters Patent, 1s

1. In a speed-indicator, the combination, with the main frame L, withinwhich is joun naled the loosely-turning worm-spindle R, of a hinged arm,IV, carrying a toothed dial, I, the main frame and arm being providedwith hand-grasps, substantially as described.

2. In a speed-indicator, the combination, with the main frame L, withinwhich is journaled the loosely-turning worm-spindle R, of a hinged arm,\V, and a spring, X, interposed between the main frame and arm,substantially as described.

3. In a speed-indicator, the combination, with the main frame L, withinwhich is journaled the loosely-turning worm-spindle 1%, of the hingedarm \V, the main frame and arm being provided with hand-grasps, and aninterposed spring, whose recoil forces the dial from the spindle at theend of the recording operation, substantially as described.

4. In a speed-indicator, the combination, with the frame L, carrying thelooselyjournaled worm-spindle It, of the hinged arm XV, carrying thegraduated toothed dial I, and provided with the set-screw Y, forlimiting the inward movement of the arm, substantially as shown anddescribed.

5. In aspeed-indicator,the combination ,with the frame L, provided withthe loosely 'ournaled worm-spindle R, of the hinged arm XV, carrying thegraduated toothed dial 1, said arm extending through an offset, V, onthe frame, and provided with the spring X and set-screw Y, substantiallyas shown and described. I

In testimony that I claim the foregoing as my own I allix my signaturein presence of two witnesses.

ltOIBEl-t. J. PRATT.

lVitnesses:

HENRY Z. PRATT, Guns. ID. BRONSON.

